Dissolver



v May 21, 1940;

"K. s VALENTINE DISSOLVER Filed March 116.. 1938 2 Sheets-Sheet l I 4 7wi May 21, 1940; K. s. VALENTINE DISSOLVER Filed March 16, 1938 2Sheets-Sheet 2 New MW M WW W Patented May 21, 1940 UNITED STATESDISSOLVER Kenneth S. Valentine, New York, N. Y., assignor to ThePatterson Foundry & Machine 00., East Liverpool, Ohio, a corporation ofOhio Application March 16, 1938, Serial No. 196,295

1 Claim.

My invention relates to an improvement in dissolvers.

The object is to provide a dissolver used in cutting cotton, or in otherwords for dissolving nitro-oellulose as used in film solution,artificial leather, pyroxylin lacquer, etc., the general characteristicsof all of these solutions being the same, since the resultant product isliquid rather than plastic, although the liquid may vary greatly inviscosity.

This dissolver may be used also for dissolving natural and syntheticresins, gums, etc., also for certain types of dispersion.

Heretoforathe equipment generally in use has not operated eificiently onvarying viscosities, for the reason that dissolving of nitro-cellulose,natural and artificial resins, gums, etc., the solutions vary from lessthan 1000 all the way to more than 2,000,000 centipoises in viscosity,and consequently it has been necessary in the past to.

use one type of machine for low viscosities, and an entirely differentmachine for high viscosities, with machines of still different designfor intermediate visco'sities.

The usual type of cotton dissolver now in use consists of a rather fiatcontainer with a turbine located in the bottom, with a stationarydeflecting ring provided to promote shear and break up the tendency toswirl. In such a machine, half second cotton can be dissolved to finalviscosity of 30,000 centipoises in thirty to forty minutes. On the otherhand, two and one-half hours are sometimes required to make a filmsolution of the same viscosity. Fifty per cent more time is required todissolve nitro-cellulose from wood pulp than is required for dissolvingthe same product made from cotton linters. For very high viscosity, thedeflecting ring is generally omitted, as there is no tendency to swirlwith the heavier material.

In the present invention, it is possible to handle the entire range fromless than 1,000 to more than 2,000,000 centipoises on the mosteconomical basis, and in the design of the present machine it will beseen that I have followed the general principle of relatively largediameter with low height, but the following additional novel featureshave been provided, which features taken together account for thedifference between the present invention and the present dayconventional dissolver, and for the advantageous results attained bythese improvements:

First, my invention comprises adjustable baffles which may be instantlychanged so that they either fold clear back against the wall of the tankwith a maximum projection of approximately one-half inch, or they beimmediately turned so that they project at right-angles with the wall ofthe tank, thus providing the optimum amount of shear or mixing actionwhere materials are to be dissolved to a final viscosity of 30,000centipoises or less, or, when the baffles are turned back fiat againstthe wall of the tank, products with a final viscosity of from 1,000,000centipoises to over 2,000,000 can be handled with the greatestexpediency, materials in the intermediate range between 30,000 and1,000,000 centipoises being most expeditiously dissolved by adjustingthe bafiies to the proper angle anywhere between the above recitedextremes to obtain the desired and most efiicient dissolving action.

From the foregoing, it will be seen that one of the objects is to attaingreat flexibility by the proper use of the adjustable baffles whichprovide a maximum efficiency at various viscosities.

By the use of this machine, the dissolving time is reduced toapproximately one-tenth of that ordinarily required for dissolving,cutting and. similar operations, consuming much less horsepower both onaccount of the reduction in time, and due to the efficient design of themachine itself.

In the accompanying drawings:

Fig. l is a view in elevation partly in vertical section; lig. 2 is aplan view on the line 22 of Fig. 1; an

Fig. 3 is an enlarged fragmentary vertical sec tion through one side ofthe tank, showing one' of the adjustable baffles in elevation.

A, represents the machine as a whole, and I, is the tank. This ispreferably of relatively large diameter and of shallow depth, although,obviously, these proportions might be changed. For instance, a talltank, with two turbines, one above the other, might be used.

A turbine 2 is keyed to the lower end of the rotary shaft 3, and theshaft is driven by the uni-power drive 4 located above the tank. Theblades of the turbine 2 are curved as shown in Fig. 2, and preferablyturned to difierent planes at their tips as fully set forth in anaccompanying application filed herewith.

Baflles 5, are pivotally mounted at intervals alongside the side wall ofthe tank, and each is provided with a handle 6 at the upper end, wherebythe bailles may be turned to suit the requirements, from outside themachine.

These adjustable bafiles are employed to satisfactorily handle materialsof various viscosities. When high viscosities are handled, the bafilesare turned close to the shell of the mixer that is out of use, but theyare adapted to be turned into the vats at increasing angles as viscositydecreases, or when less viscous materials are handled and when requiredat various intermediate points.

This open, curved blade type of turbine either with or without a stator,depending upon the material being dissolved, as Well as the use of atank with a dished bottom 9, is preferred and hence illustrated, butthese features are not necessarily essential to the present inventionwhich resides largely in the use of the adjustable baflles. They afforda means of regulating the degree of rotating action of the materialbeing handled. By their use, swirl is prevented and thus a batch ofeither thin or viscous materialv may be handled in this same machinewith equal efiiciency.

the bafiles.

A man-hole I is formed in the top of the tank, and a discharge outlet 8at the bottom.

I claim:

The combination of a tank having a cylindrical intermediate portion, arotatable shaft located in the tank, an impeller carried by the shaftand having blades, each blade having a portion in a vertical plane andbeing inclined toward its tip, baffles pivotally supported in the endsof the tank, with one edge contiguous to the cylindrical wall andextending substantially throughout the height of the latter, whereby allmaterial within the tank forced against and following the wall of thetank, is deflected by the baffles when they are turned outwardly,thereby retarding and turning back the material in the direction of theimpeller, and means outside of the tank for regulating the axialposition of KENNETH S. VALENTINE.

